This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.

Abstract

The genetic composition of the resident Symbiodinium endosymbionts appears to strongly modulate the physiological performance of reef-building corals. Here, we used deep amplicon sequencing to quantitatively assess Symbiodinium genetic diversity for the two mountainous star corals, Orbicella franksi and Orbicella faveolata, from two reefs separated by 19 kilometers of deep water. We aimed to determine if symbiont diversity is largely partitioned with respect to coral host species or geographic location. Our results demonstrate that across the two reefs both coral species contained only Symbiodinium identifiable as clade B type B1, represented by five distinct haplotypes. Three of these haplotypes have not been previously described and may be endemic to the Flower Garden Banks. No consistent differences in symbiont composition were detected between the two coral species. However, significant quantitative differences were observed between the east and west banks for two of the five haplotypes. These results highlight the need for consistent molecular genotyping techniques to assess local community assemblages of Symbiodinium-host relationships, which could be largely irrespective of host genetic background. This deep-sequencing approach used to sensitively characterize cryptic genetic diversity of Symbiodinium will potentially contribute to the understanding of physiological variations among coral populations.

Supplemental Information

Analysis of Molecular Variance (AMOVA) Fixation index (FST) values showing no genetic differentiation among Orbicella faveolata and Orbicella franksi, among Orbicella faveolata within the two geographic locations or among Orbicella franksi within the two geographic locations.

Only showing significant results from Poisson-lognormal Generalized Linear Models (GLMs). Haplotypes IV and V are significantly diminished at the west bank compared to the east bank (PMCMC<0.001). Haplotype V is also significantly more diminished in Orbicella faveolata than in Orbicella franksi (PMCMC=0.002).

Field Study Permissions

Funding

Research was funded by the National Science Foundation grant DEB-1054766 to MVM and IOW 0644438 and IOS 0926906 to Mónica Medina, and the PADI Foundation Award to SWD. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Add your feedback

Before adding feedback, consider if it can be asked as a question instead, and if so then use the Question tab. Pointing out typos is fine, but authors are encouraged to accept only substantially helpful feedback.

Follow this preprint for updates

"Following" is like subscribing to any updates related to a preprint.
These updates will appear in your home dashboard each time you visit PeerJ.

You can also choose to receive updates via daily or weekly email digests.
If you are following multiple preprints then we will send you
no more than one email per day or week based on your preferences.

Note: You are now also subscribed to the subject areas of this preprint
and will receive updates in the daily or weekly email digests if turned on.
You can add specific subject areas through your profile settings.